Last updated: February 24, 2025
In September, Shelter Island showcases a blend of mild temperatures and refreshing coastal air, with a maximum reaching 26°C (79°F) and an average of 20°C (69°F), while nights dip to a comfortable 12°C (55°F). This transitional month brings a total precipitation of 99 mm (3.9 in) over approximately 10 days, promoting lush greenery and vibrant landscapes. With humidity hovering around 75%, visitors can expect a pleasant maritime climate, perfect for outdoor activities and exploration of the island's natural beauty.
September in Shelter Island marks a transition towards cooler autumn days while still embracing mild summer warmth. With temperatures ranging from a minimum of 12°C (55°F) to a comfortable maximum of 26°C (79°F), the average temperature settles at a pleasant 20°C (69°F). This month captures the best of both seasons, allowing for cozy sweater weather in the evenings and warm afternoons perfect for outdoor activities. As the days shorten, the lingering warmth of summer begins to fade, setting the stage for the cooler months ahead while ensuring that September remains a delightful time to explore the island’s natural beauty.
In September, Shelter Island experiences a notable pattern in precipitation, with 99 mm (3.9 in) of rainfall over approximately 10 days. This maintains a consistent trend seen throughout the summer, with September's rainfall mirroring July and August quite closely. This month serves as a transitional phase as summer gives way to fall, and while the rainfall is somewhat moderate, it hints at the wetter months ahead. As October approaches, the precipitation significantly increases, indicating a shift in climate dynamics that often brings heavier rains and more frequent storm events. Overall, September represents a balancing act between the dry heat of summer and the impending wetness of autumn, making it a pivotal month in the yearly climate cycle of Shelter Island.
As September rolls in on Shelter Island, the humidity begins to show signs of subtle decline, settling at an average of 75%. This marks a slight drop from the summer months of July and August, where humidity levels hovered at 76%. Following a trend of decreasing moisture that started in late spring, September's comfortable humidity levels invite locals and visitors alike to revel in the early autumn ambiance. The overall pattern reveals a gradual transition from the higher humidity of winter months, which peak at 84% in January and February, to the drier conditions of fall, maintaining a delightful balance perfect for outdoor activities.
As summer transitions into fall, September on Shelter Island maintains a very high UV Index of 8, with a burn time of just 15 minutes. This indicates that while temperatures may begin to drop, the sun's intensity remains significant, encouraging sun protection during outdoor activities. Notably, the UV Index this month shows a decrease from the peak values of 10 that characterized July and June, yet still requires vigilance similar to the earlier summer months. This trend reflects the gradual shift towards less intense sunlight, paving the way for more moderate conditions in October. For detailed insights on sun exposure, visit Shelter Island UV Index.
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As summer gives way to fall, September in Shelter Island offers a delightful balance of warmth and sunlight, boasting 281 hours of sunshine. This pleasant month follows the peak summer months of July and August, which recorded 349 and 327 hours, respectively, highlighting the region's sunny splendor. While September enjoys a slight decrease in sunlight hours, it still stands out as one of the sunniest periods of the year, promising bright skies and perfect days for exploring the island's natural beauty. As the year progresses, the gradual decline in sunlight leading into October with 229 hours suggests a gentle transition towards cooler, cozier days, while still allowing plenty of time to savor the lingering warmth of summer.
September in Shelter Island brings a notable consistency in sunny weather, showcasing a 49% chance of sunshine, tied with January and April. As summer fades, the likelihood of clear skies remains robust, hinting at a pleasant transition into fall. Notably, this month does not experience the low expectations seen in August, which dips to 35%. Instead, September offers a refreshing balance, reminiscent of the sunny days of spring and early summer, making it a delightful time to enjoy outdoor activities. With the autumn breeze starting to set in, residents and visitors alike can relish a chance for sunny days while savoring the beauty of the changing season.
As September arrives in Shelter Island, residents and visitors experience a gentle shift in daylight duration, with 12 hours of daylight marking the month's rhythm. This subtle decline from the 14 hours enjoyed in May and June signals the gradual transition into autumn. After a summer filled with abundant light, the decreasing hours not only remind us of the changing seasons but also offer a chance to savor the warm hues of early fall. Following September, daylight hours continue to dwindle, dipping to 11 hours in October, as nature prepares for the more introspective months ahead. This trend highlights the cyclical nature of time, encouraging us to embrace the fleeting beauty of each season.
As September rolls into Shelter Island, a gentle uptick in wind speed offers a refreshing contrast to the calmer summer months. The average wind speed reaches 6.1 m/s (14 mph), a noticeable rise from July and August, which hovered around 4.8 m/s (11 mph). This shift signals a transition into the fall season, where the blustery breezes begin to invigorate the landscape. Looking at the trends throughout the year, it's evident that after a steady decline from the early months, September brings a welcome revival in wind activity, paving the way for the breezier autumn ahead. With October and November also boasting speeds around 6.7 to 6.8 m/s (15 mph), the increased winds encapsulate the island's vibrant seasonal change, making each day an inviting opportunity for outdoor adventures.
The weather in Shelter Island changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Shelter Island and find detailed weather information for every month.
September brings a more temperate climate, with average temperatures hovering around 20°C (69°F) and maximums reaching up to 26°C (79°F). This month experiences a fair amount of rainfall, averaging 99 mm (3.9 inches) over about 10 days, combined with a humidity level of 75%. In stark contrast, January presents a much colder scene, with average temperatures plummeting to just 2°C (37°F) and maximums only reaching 13°C (56°F). This winter month has slightly less precipitation, averaging 89 mm (3.5 inches) over 9 days, but with a higher humidity level of 84%. For more detailed information about January conditions, check out Shelter Island weather in January.
September and February present two starkly contrasting weather experiences. September enjoys milder temperatures, ranging from a minimum of 12°C (55°F) to a comfortable maximum of 26°C (79°F), with an average of 20°C (69°F). This month, however, also brings a fair amount of precipitation, totaling 99 mm (3.9 in) over about 10 days, accompanied by moderate humidity at 75%. In contrast, February is significantly colder, with temperatures plummeting to a minimum of -12°C (11°F) and peaking at only 12°C (53°F), averaging just 3°C (37°F). Additionally, February is wetter, experiencing 123 mm (4.8 in) of rainfall over 11 days and higher humidity at 84%. For more details on the February weather, you can check out Shelter Island weather in February.
In comparing the weather of September and March, a stark contrast emerges. September boasts a milder climate with average temperatures ranging from a minimum of 12°C (55°F) to a maximum of 26°C (79°F), along with humidity levels of 75% and 99 mm (3.9 in) of precipitation over 10 days. In contrast, March presents a much colder scenario, with average temperatures starting from a chilly -7°C (20°F) to a maximum of 15°C (59°F). The precipitation in March is slightly higher at 113 mm (4.5 in) but maintains a similar frequency with rain on 10 days, while humidity rises to 82%. For a more in-depth look at the weather specifics, check out Shelter Island weather in March.
In comparing the weather of September and April, September generally offers milder temperatures with an average of 20°C (68°F) compared to April's cooler 8°C (47°F). While September enjoys a maximum of 26°C (79°F), April's peak temperature is only 16°C (61°F), making September feel significantly warmer. However, April experiences higher precipitation levels at 137 mm (5.4 in) over 12 days, compared to September's 99 mm (3.9 in) across 10 days. Despite this, September's humidity is slightly lower at 75% compared to April's 79%, which can affect comfort levels. For a detailed look at April’s weather specifics, you can check Shelter Island weather in April.
In comparing the weather of September and May, September tends to be warmer, with average temperatures reaching 20°C (69°F) and maximums of 26°C (79°F), while May has a cooler average of 12°C (54°F) and a maximum of 20°C (69°F). However, May experiences slightly higher precipitation, with 129 mm (5.1 in) falling over 13 days, compared to September's 99 mm (3.9 in) over 10 days. Both months have consistent humidity levels of 75%, but the overall climate in September feels more pleasant and inviting for outdoor activities. For more details on May's climate, check out Shelter Island weather in May.
When comparing the weather in September to that of June, September typically features slightly warmer temperatures, with an average of 20°C (69°F) compared to June's 18°C (64°F). The maximum temperatures also rise to 26°C (79°F) in September, while in June, they peak at 24°C (75°F). Additionally, September experiences more precipitation, totaling 99 mm (3.9 in) over about 10 days, whereas June sees 72 mm (2.9 in) over 8 days. Humidity levels remain comparable, with September at 75% and June at 78%. For a closer look at June weather specifics, you can check this link: Shelter Island weather in June.
In comparing the weather between September and July, we find that September tends to be slightly cooler, with average temperatures ranging from a minimum of 12°C (55°F) to a maximum of 26°C (79°F), while July features warmer conditions, with temperatures ranging from a minimum of 16°C (61°F) to a maximum of 28°C (82°F). Both months receive the same amount of precipitation, at 99 mm (3.9 in) over 10 days, though September experiences slightly higher humidity at 75% compared to July's 76%. This means that while July is generally warmer, September offers a more moderate climate as summer transitions into fall. For a closer look at July weather specifics, check out Shelter Island weather in July.
In comparing the weather of August and September, it’s clear that September experiences slightly cooler temperatures, with a minimum of 12°C (55°F) compared to August's 17°C (63°F). The average temperature in September is around 20°C (69°F), which is a few degrees lower than August's average of 23°C (73°F). Additionally, September sees a similar amount of precipitation at 99 mm (3.9 in) over 10 days, while August has a slightly higher total of 103 mm (4.0 in) over 9 days. Humidity remains relatively consistent, with September at 75% and August at 76%. For more details on August weather conditions, you can check Shelter Island weather in August.
September typically experiences milder temperatures, with average highs reaching 26°C (79°F) and lows around 12°C (55°F). This month sees about 99 mm (3.9 in) of precipitation over approximately 10 days, offering a comfortable yet slightly humid atmosphere with a humidity level of 75%.
In contrast, October ushers in cooler weather, with average temperatures dropping to a maximum of 24°C (75°F) and a minimum of 5°C (42°F). This month experiences a notable increase in rainfall, totaling 160 mm (6.3 in) across about 14 days, while maintaining the same humidity level of 75%. The transition from September to October signifies a shift towards more variable weather conditions. For more detailed insights, check out the Shelter Island weather in October.
In September, temperatures are notably milder, with averages around 20°C (69°F) and maximums reaching 26°C (79°F), while November sees a significant drop, averaging 10°C (50°F) and maxing out at 19°C (67°F). Precipitation levels are similar in both months, with September receiving 99 mm (3.9 in) and November slightly wetter at 113 mm (4.4 in), though both months experience rainfall on about 10 days. Additionally, humidity levels are higher in November at 80%, compared to 75% in September, contributing to a colder and more brisk atmosphere as the season transitions. For a more detailed look at November's weather, you can visit Shelter Island weather in November.
The contrast between September and December weather is quite pronounced. In September, temperatures are generally milder with averages around 20°C (69°F), peaking at 26°C (79°F), while December brings a significant drop, with average temperatures of just 5°C (42°F) and maximums reaching only 16°C (61°F). Precipitation also varies, with September seeing 99 mm (3.9 in) over about 10 days, in contrast to December’s higher 147 mm (5.8 in) across 12 days. Additionally, humidity levels in December are slightly higher at 80%, compared to September’s 75%. For a more detailed look at the weather during December, check out Shelter Island weather in December.
As summer gives way to autumn, September on Shelter Island showcases a delightful transition in weather. With a pleasant average temperature around 20°C (69°F), this month offers a refreshing respite from the heat, while still allowing for the warmth of sunny days. However, it also brings an increase in humidity and a fair share of precipitation, with about ten days of rain contributing to the island's lush landscapes. This unique blend of moderate temperatures and occasional showers makes September a special time to experience the island's beauty. For a deeper dive into what to expect year-round, visit Shelter Island Climate.